The invention relates to an apparatus for the optical measurement of substance concentrations, having a transmitter and a receiver for optical radiation of the type defined in more detail in the preamble of claim 1.
A generic apparatus is known, for example, from DE 93 19 750 U1. Such apparatuses, generally also referred to as immersion probes, are usually used to analyze liquids for example in chemical, biological and pharmaceutical research, production and inspection. However, they are also used in bulkable substances, such as powders or granules. Here, optical radiation, usually light, is used to measure the absorption effected by the medium when it is permeated by the optical radiation.
In practice, a frequent problem with such apparatuses is that it is necessary in some applications to measure varying layer thicknesses of the substance. To this end the measurement probe and/or the deflection device for the optical radiation need to be replaced in the known apparatuses, which results in disruptions to the operation which are sometimes significant.
It is therefore an object of the present invention to provide an apparatus for the optical measurement of substance concentrations which can be used to measure varying layer thicknesses of substances to be examined with relatively little complexity.
This object is achieved according to the invention by way of the features mentioned in claim 1.
The adjustment device according to the invention makes it possible to change the distance between the deflection device and the transmitter and/or the receiver in a way such that the layer thickness of the substance to be measured can also be varied during the measurement. Advantageously, as a result, no more disruptions to the operation are necessary, which leads to a significant saving in terms of time and thus costs.
This variability of the layer thickness of the substance to be measured makes it possible in addition for the sensitivity of the apparatus to be matched very easily to the respective measurement task. It is another advantage of the adjustment device according to the invention that the deflection device can in this way be moved to a different location, for example in order to be cleaned.
A very simple and practicable embodiment of the invention can provide for the adjustment device to have at least one holding element and a displacement element which is mounted in the at least one holding element such that it can be displaced, with one of the components of the adjustment device being connected to the housing and the other component being connected to the deflection device.
An embodiment of the adjustment device in which the latter can be adjusted manually is particularly simple and thus cost-effective.
In order to make the operation of the adjustment device more convenient, it can, however, also be provided that the latter can be adjusted by electrical, hydraulic or pneumatic means.
In another very advantageous embodiment of the invention, the deflection device can be adjusted with respect to the transmitter and the receiver in a manner such that the deflection device forms a closed hollow space with the housing.
This closed hollow space makes it possible to carry out reference measurements on substances introduced into the hollow space without removing the apparatus from the substance, which can likewise contribute to the simplification of the process.
If in this connection a flushing device for flushing the hollow space between the housing and the deflection device is provided, simple flushing of the hollow space and thus cleaning of the surfaces surrounding the hollow space is possible, likewise without having to remove the apparatus from the substance. In this case it is furthermore possible to introduce reference media into the hollow space.
Other advantageous refinements and developments of the invention emerge from the remaining dependent claims. Exemplary embodiments of the invention will be illustrated in terms of their principle below with reference to the drawing, in which: